I have had a couple chains break on me while cutting. Luckily enough they have just fallen to the ground nothing too crazy like some have experienced. I’m also an advocate of a hard hat of some sort after I got 34 staples in my head last spring after taking a branch to the head. Should have been my last day but I took it as a lesson from the man upstairs to start thinking about safety and less about hurry up and get it done! You can do everything right and still have freak things happen.

Broken a couple over the years. I suspect it is most often a result of throwing the chain off the bar and compromising a link.

"a fail on the saw shop end"

Had a new 3/8 chain that needed
shortened. Tech used a 404 preset.
Stihl chain, Stihl shop. What could go wrong?

Check everything.

if there is one plus side to taking your chains in for sharpening , it is a lot less likely they leave you enough cutter that you sharpen more then 8 times

where you might run a chain a very long time if you keep it out of the dirt and hand file.

Interesting. I figured out my Husky 350 has this safety feature.

We always grease the bar sprocket every tank of gas. One or two squeezes on the grease gun is all it takes.

Not all bar brands have grease holes.
I'm also a greaser, clutch bearings too.